EDM drill

ABSTRACT

An EDM drill comprised of an automated electrode tube replacing means to allow fully automated and continuous working on holes; and further comprised of an electrode tube guide selection device to allow fully automated and continuous working on holes of various diameters.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] This application is a Continuation-in-Part of my applicationfiled Aug. 29, 2000, Ser. No. 09/649,601.

[0003] The present invention relates to an EDM drill, and moreparticularly, to one comprised of an electrode tube changer and guidechanger capable of replacing, and selecting an electrode tube and guideto achieve fully automated and continuous operation of hole dischargeprocessing (drilling) on work pieces of different thickness and holesize.

[0004] (b) Description of the Prior Art

[0005] Please refer to FIG. 9.

[0006] EDM drilling: Chucking an electrode tube (P) on a spindle. Adjusta W-axis (W) on an X-axis (X) and a Y-axis (Y) to a starting position ofa work piece. Move an electrode tube guide (G) of the W-axis (W) towhere above the work piece at a proper height while allowing theelectrode tube (P) pass through the guide (G). Activate a C-axis (C) torotate the electrode tube (P) and mostly supply the dielectric fluid,and control a Z-axis (Z) movement according the condition between theelectrode tube (P) and the work piece to drill a hole into the workpiece by electrical-discharge power.

[0007] The prior art is observed with the following limitations: (1) Itis difficult to automatically replace the electrode tube since theelectrode tube practically gives no rigidity. For that reason, itprevents the use of a device like an ATC (Automatic Tool Changer) thatis used by a machining center to chuck the electrode tube to the spindletoday. (2) It prevents the automatic selection of a different guide sizewhich is needed to hold different size of electrode in order to drilldifferent size of hole.

SUMMARY OF THE INVENTION

[0008] The first purpose of the present invention is to provide an EDMdrill which contains a means for automated exchange of the electrodetube. The consumed electrode tube or the electrode tube with a lengthnot sufficient for the next round of process is automatically replacedto ensure the continuous and automated processing.

[0009] Another purpose yet of the present invention is to provide an EDMdrill, containing further a means for selecting an electrode tube guideso to process holes of different sizes continuously and automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a front view showing the operation of unloading anelectrode tube storage device and a spindle nut of the presentinvention.

[0011]FIG. 2 is a top view of the electrode tube storage and carrouseldevices of the present invention.

[0012]FIG. 3 is a perspective drawing showing the electrode tube storagedevice and the spindle nut assembly of the present invention.

[0013]FIG. 4 is a side view showing the operation of loading theelectrode tube storage device and the spindle nut of the presentinvention where screw threads of the spindle and the spindle nut are notengaged.

[0014]FIG. 5 is a side view showing the operation of loading theelectrode tube storage device and the spindle nut of the presentinvention where screw threads of the spindle and the spindle nut areengaged.

[0015]FIG. 6 is a front view of the guide selection device of thepresent invention.

[0016]FIG. 7 is a side view of a guide selection device of the presentinvention.

[0017]FIG. 8 is an exploded drawing showing a guide holder used by theguide selection device of the present invention.

[0018]FIG. 9 is a drawing of a prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As illustrated in FIGS. 1 and 2, the preferred embodiment of thepresent invention is comprised of an electrode tube storage device (4)and an electrode tube guide selection device (5) (also refer to FIGS. 6and 7). The electrode tube storage device (4) is comprised of aplurality of electrode tube storage units (41) and other components toform a mobile electrode tube carousel (42), which is connected to engagein a cyclic movement. The preferred embodiment also contains a W-axis(31) operating on the existing an X-axis (1), or a Y-axis (2) and aspindle (6). Wherein, the X-axis (1) extends itself to become anextended X-axis ( 11) to provide access to the electrode tube storagedevice (4). The construction of a cyclic connection conveyer for theelectrode tube carousel (42) is formed with cyclic chains. Under normalcondition, a spindle nut (61), an electrode tube (7) and a leak-proofseal (71) are provided to each electrode tube storage unit (41). Inoperation, the electrode tube storage carousel (42) may deliver a singlestorage unit (41) in cycle to a designated point in position while theW-axis (31) moves at the X-axis (1), or the Y-axis (2) and the extendedX-axis (11) to where above the electrode tube (7). The W-axis (31) alsomoves longitudinally parallel to a Z-axis (3) and the spindle (6) turnsclockwise or counter-clockwise to load or unload the electrode tube (7).

[0020] The electrode tube guide selection device (5) can turn to anyselected guide unit (56) with a proper size guide (564) on it for theinsertion by the electrode tube (7).

[0021] As illustrated in FIG. 4, the electrode tube storage unit (41) ofthe present invention relates to a rigid member (411) comprised of anelastic member (412) to absorb change in length resulted while combiningor releasing the spindle nut (61) by the spindle (6), and a holder (413)to store and restrict the rotation of the spindle nut (61). Wherein, theholder (413) of the spindle nut (61) can be provided at the upper end ofa frame (411) while a corresponding concave that can hold local profileof the spindle nut (61) is provided on the holder (413). An electrodetube-guarding duct (414) is provided on the frame (411) and athrough-hole (not illustrated in the accompanying drawings) inupside-down cone shape is formed inside the electrode tube-guarding duct(414), which is used to protect the stored electrode tube from shakingtoo much during carousel movement.

[0022] The spindle nut (61) as illustrated in FIG. 3 has a nut (611)containing a collet (612) and the collet (612) chucks both of theelectrode tube (7) and its leak-proof seal (71). Female threads (6111)inside the nut (611) and male threads (62) provided at the lower end ofthe spindle (6) are tightened or loosened to load or unload the spindlenut (61), the seal (71) and the electrode tube (7) as a whole unit.

[0023]FIG. 4 shows the cutaway view of chucking the electrode tube (7).Wherein, the spindle (6) descends until it holds against both of the nut(611) of the spindle nut (61) and the holder (413) [The nut (611)contains the collet (612), the electrode tube (7), and the seal (71)] topress against the holder (413). So the holder (413) descends andcompresses the elastic member (412) to a proper position but not all waydown to the end. At this time, the spindle (6) turns clockwise to engageboth of the spindle nut (61) and the spindle (6) while chucking tightlythe collet (612). The seal (71) is pressed and the electrode tube (7)properly chucked. Meanwhile, the elastic member (412) pushes back theholder (413) for the holder (413) to maintain restricting the nut (611)from rotating until it is screwed into the spindle (6).

[0024] As illustrated in FIG. 5, while unloading the electrode tube (7),both the spindle (6) and the spindle nut (61) are descending to wherethe nut (611) merely presses against and descends the holder (413) untilthe nut (611) clears away from the spindle (6). Wherein, the elasticmember (412) absorbs the change in length or the movement of thereleasing nut (611). That is, the spindle (6) creating a movement of thespindle nut (611) by fastening or releasing the spindle nut (611), andabsorbing the movement of the spindle nut (611) by the elastic member(412).

[0025] As illustrated in FIGS. 6 and 7, the preferred embodiment of theguide select means of the present invention is comprised of an encoder(51), a motor (52), a brake (53), a gear (54), a rotating plate (55), aplurality of guide units (56), a home position plate (57). Wherein, theencoder (51) gives the turning angles of the rotating plate (55) or themotor (52). The brake (53) is used to restrict the gear (54), but thebrake (53) may be unnecessary in case of that the backlash of the gear(54) is not big enough to affect the positioning accuracy. The gear (54)is fixed to the rotating plate (55) while the circumference of saidrotating plate (55) is used to hold the guide unit (56) in position. Thehome position plate (57) is fixed to a turning shaft of the rotatingplate (55). A mark (571) is protruding from the home position plate (57)by a sensor (572) in a cycle of rotation by the home position plate(57).

[0026]FIG. 8 shows the detailed construction of the guide unit (56). Asshown in FIGS. 6 and 7, the guide unit (56) is comprised of a fixationplate (561), a slide (562), a guide a holder (563), a guide (564) and ahopper (565). An oval opening (not illustrated) is provided below thefixation plate (561) (not illustrated) for a bolt (5611) to go throughand fix to the rotating plate (55) and for inching the relative positionbetween the guide unit (56) and the rotating plate (55). A dovetail(5612) is provided to the fixation plate (561) so to relatively caulk toeach other with the slide (562) while inching their relative positions.The slide (562) is further connected with a bolt (5633) to the guideholder (563) whereupon the guide (564) is provided. A plurality ofgrooves (5631) are provided on the guide holder (563), and a pluralityof bolting holes (5632) and bolts (5633) are provided on the guideholder (563). The grooves (5631) are in parallel on a horizontal planewhile the bolting holes (5632) are at a right angle to the grooves(5631) and bolted to bolts (5633). Once the bolt (5633) rotates, spaceinclination of the grooves (5631) changes accordingly for inching thevertical degree of the guide unit (56), thus making the guide unit (56)is in the same axis with that of the spindle (6), as illustrated in FIG.9. The hopper (565) is used to guide the electrode tube (7) into theguide (564).

[0027] In the preferred embodiment, at least one set of the guide unit(56) may be provided on the rotating plate (55) and the encoder (51) maybe used to give the rotating plate (55) or the motor (52) for automatedcontrol the rotation angle of the rotating plate (55), thus the guide tothe guide unit (56) required can be turned to stop at a proper positionfor the electrode tube (7) descending along the Z-axis (3) to passthrough the guide (564) and achieve the purpose of selecting the desiredguide (564). The reference point in the preferred embodiment is definedby the mark (571) of the home position plate (57). Once the motor (52)starts, the sensing by a sensor (572) is designated as the marker (571)of starting point for the determination and control to ensure that theguide unit (56) rotates to its correct position.

I claim:
 1. A tube storage unit in a tube electrode changer for anelectro-erosion drilling machine is used to store a threaded spindlenut, by working together with a threaded spindle to provide a method ofloading an electrode tube to said spindle, or unloading an electrodetube from said spindle, and a method having characteristics of: a)having screw threads on both said spindle and said spindle nut and byrotating said spindle, said spindle nut is attached or detached to saidspindle by controlling a rotating direction of said spindle; b) having aconcave at a position of setting said spindle nut to hold said spindlenut from turning during rotating of said spindle, so that said threadswill be engaged to or disengaged from said spindle, and c) having anelastic member to absorb a displacement created during attaching anddetaching said spindle nut and to provide a threading tension.
 2. Anautomatic tube guide changer for an electro-erosion drilling machinecomprising a rotating plate, a plurality of guide units on a plate, anelectrode tube inserted in a guide which is mounted to one of said guideunits, and having characteristics of changing the guide to another,comprising a) ascending said spindle such that said electrode tube iscompletely out of said guide unit; b) rotating said rotating plate to aposition that said guide unit which holds said desired guide directlyunder the spindle, and c) descending said spindle to insert saidelectrode tube into said guide.
 3. An automatic electrode tube changerfor an electro-erosion drilling machine comprising a spindle havingscrew threads, at least one spindle nut, at least one tube storage unit,said tube storage unit is used to store a threaded spindle nut, byworking together with a threaded spindle to provide a method of loadingan electrode tube to said spindle, or unloading an electrode tube fromsaid spindle, and a method having screw threads on both said spindle andsaid spindle nut and by rotating said spindle, said spindle nut isattached or detached to said spindle by controlling a rotating directionof said spindle, and having a concave at a position of setting saidspindle nut to hold said spindle nut from turning during rotation ofsaid spindle, so that said threads will be engaged to or disengaged fromsaid spindle, and having an elastic member, a displacement createdduring attaching and detaching said spindle nut is absorbed and anecessary threading tension is also provided, and exchanging saidelectrode tube on said spindle characterized by: a) position saidspindle over one said tube storage unit without one said spindle nut onsaid tube storage unit; b) unload an electrode tube on said spindle; c)position said spindle over a desired tube storage unit with one saidspindle nut on said tube storage unit, and d) load an electrode tube onsaid spindle.
 4. A guide holder for an electro-erosion drilling machineis used to hold a guide and allows an alignment of said guide toparallel a travel of said spindle characterized by: having a body withbolting holes, in order to do said alignment, a plurality of grooves areprovided on said body to make it elastic enough in said alignmentdirection, and bolts are used to hold said body to deflect said groovesto complete said alignment of said guide.